What adventure would you recommand to 1est levels for forgotten realms setteings?
One that won't get them killed... 
Seriously though, it would help to know what era you're planning on setting it in, and any ideas you might have had about the region you want to base the campaign out of. Those are both rather looming influences in any recommendation one might offer, as are things like what sort of mood or theme the group is interested in. If you just want a simple dungeon crawl, then obviously none of that matters too much beyond background noise, but if you're looking for a long term campaign, it's kinda vital to know. Narrow the parameters and you'll probably get more useful answers than just tossing a net out and praying. 
Stigger wrote:
Check out the old DnD encounters stuff. Great intro for a GM and great intro for the players. They're cheap and well put together.
I would suggest going with a simple Homebrew, maybe helping a Noble or some Trade Coster fight off Bandits or Orcs. Perhaps some wayside inn along the road to Waterdeep has a mysterious traveler stop for the night. A local Bandit Lord has set up a stronghold or camp in some ruins. That lord could be a former Zhent or a Red Wizard or just a mean Ogre. Perhaps the Ruins have some ancient secret from ages long Forgotten that the bandits may or may not know about.
Focus on a small goal, a double handful of noted NPC's to put some gold in the players hands and let them build the reputation they seek to be with their characters. Get a feel for who your players plan to be how they react under pressure. Also think about what the Players are going to be, what they are and where they are from. I like to build my game around the Player's Characters and then look out into the Realms and see where or what yarn I might be best to spin around this group. Those little possible stories or rumors they hear from a drunken bard or bitter locals, the notes upon the work order board, maybe an old treasure map, diary, or fragmented blade from the merchant shop or below a loose board in the floor of their room at the Inn. See where they might go and be ready for anything 
Heck, throw in a Harper NPC, but don't let them in on those who Harp unless they figure it out for themself.
Selecting a geographic area adds color to your description of NPC's, local areas, history/legend/lore and perhaps some whispers of what might be the campaign you decide to choose as a main adventure as a cliff hanger for the next game session. It may allow you as a DM to decide how to present your Major Campaign and what avenues you might choose to take to get the Players envolved.
Having an entire party of dwarves/halflings/elves/tieflings might determine how or what kind of adventure they end up grasping for and would help you as a DM deciding how the NPC's recieve them. I'm stoked just thinking about starting a fresh new game now 